Does anyone here know if this is ok to do on the same day? For instance, start off in morning with sprints, then later in day do some squats? Or, do some rows and chin ups then to HIIT rowing? Or maybe vary muscle groups, like on the sprint day do upper body/back and on HIIT rowing day do squats/deadlifts/lunges or whatever. Anyone done this at all, or at least have some knowledge to whether or not it is a good idea? I would to do HIIT and weightlifting, but only 5 days a week so I have been condensing it lately and doing it on same day. Just wondering if I am dooming myself or if it is more productive, since it has been too little of time for me to really tell

I do both the same day, during the same time frame as well. I do my weight training, then rest about 10-15 minutes and do a HIIT session. I train 3 days a week and try to be active on the off days.

If your going to do them in seperate sessions I don't see any problem doing the HIIT first (in the morning) followed by the weights (in the evening). But if you do them at the same time, do weights first.